Australian farmers could be about to get an unusual new weapon to protect their crops from rampaging kangaroos.

Researchers in Melbourne have found that these voracious marsupials can be scared off by the thumping sound of their own large feet on the ground.

There could be as many as 60m kangaroos in Australia, and they often compete with livestock for food and water.

Keeping these fleet-footed marsupials away from their crops and water supplies has become a constant battle.

A traditional deterrent has been a series of high pitched squeals emitted from loudspeakers.

Researchers have found that kangaroos often become accustomed to these artificial sounds and take little notice of them.

However, a recording of a 'roo thumping its foot appears to have been quite a breakthrough. This is the noise these macropods make when they sense danger before taking flight.

Using the animal's own alarm system could be what irate farmers have been looking for. They often complain that kangaroo numbers have reached plague-like proportions. Several million are shot dead every year as part of an official cull.

Animal rights campaigners have insisted that many of these pouched mammals die a painful death at the hands of unlicensed or inexperienced marksmen.

A large number of marsupials are also killed or injured on Australian roads by cars and trucks. Researchers, who are hoping to develop their foot thumping technology, believe it could also be used to guide kangaroos away from busy highways.